Fire control mechanism



.1. WF. HABERLIN FIRE CONTROL MEGHANISM Filed Dec. ,2, 1939 y 3 Sheets-Sheet l humid; F. Hdwwlin m L R E E A H F. uw.

FIRE CONTROL MECHANISM Filed Dec. 2, 1939 5 Sheets-Sheet 2 Mm, KME, J. F. HABERLIN 2,304,566

FIRE CONTROL MECHANISM Filed Deo. 2, 1939 3 Sheets-Sheet 5 snventor est .lohnlF'. Haberlin, Seattle, Wash., assigner, by

mesne assignments, to Boeing Aircraft Company, Seattle, Wash., a corporation of Washgt application December 2, 1939, Serial No. 307,273

(Cl. Sil-27) laims.

This invention relates to military airplanes, and more particularly to a single-seated airplane of the pursuit or fighter type. The invention is concerned with the provision of means whereby the pilot of such a single-seated fighter may protect himself from attacks from the rear.

Single-Seated military planes are normally armed with one or more machine guns, directed forwardly, since such airplanes are intended prigun in a single-seat airplane. and to adjust it to nre in either of two positions; for aiming, two separate aiming means have been provided, one fixed with relation to one position of the gun, and the other iixed with relation to the alternative position ofthe gun. This ail'ords some measure of protection to the pilot, but still if an enemy airplane attacks from the rear and within the necessarily fairly wide angle between the two firing positions, the only protection for the pilot is to maneuver. Maneuvering breaks up formations, and destroys the protection of the mass of iire of the whole formation, besides interrupting forward progress and perhaps leaving a convoyed marlly as fiighters to pursue and attack larger formation open to attack. It is therefore preferairplanes, such as bombers, while in flight, and able so as to arrange the ire power of such fighter they are normally so fast that reliance is placed airplanes that they may, without breaking forupon their speed to avoid attacks upon them from mation, deal with any enemy approaching from the rear. However, whenever a group of bombthe rear throughout the whole of any angle which ing airplanes convoyed by pursuit planes is at- 1 5 permits the enemy to bring to bear eiiective and tacked by enemy pursuit planes, there immesustained fire from his forwardly-firing guns. diately ensue combats between individual pursuit However, it has not been deemed possible heretoplanes of approximately equal speed and maneufore, so far as I am aware, to provide a rearverability, and in such dog flights each lighter, wardly directed gun in a single-seated fighter, knowing that the other has only forwardly di- '20 and to arrange sighting means for such a gun, rected machine guns, endeavors to keep out of the properly coordinated therewith, in such a way forward line of re of his opponent, and instead that the single occupantof the airplane could to place himself on the tail of his opponent, where eiectively fire the gun at an opponent on his he can destroy his opponent with forwardly ditail. The provision of means to this end is the rected re from his own guns. The fighter who ,25 primary object of this invention. permits an opponent thus to gain the advantage If such a gun were a xed gun, it would probof a position on his tail has no defense other than ably re either above or below the elevator and skillful maneuvering. Occasionally, too, an airhorizontal stabilizer, although, indeed, two such plane or a patrol may be attacked by enemy airguns might be carried, one pointing above and planes which, without being seen, attain a posione below these control surfaces; but in any tion on their tail. event, if such rearwardly directed guns were It is the principal object of the present invenknown by the enemy to be fixed in position, or tion to afford to such a single-seated fighter only capable of firing in one of two divergent plane the advantage of a rearwardly directed directions, their line or lines of re would be gun, whereby should its pilot find an opponent avoided. ft is therefore a further object of the upon his tail, he can destroy the opponent inpresent invention to provide means to adjust stead of being himself destroyed, or being forced such rearwardly directed guns in a single-seated to maneuver to escape attack. i military airplane, for aiming them, and, more- It is known in larger airplanes to provide rearover, to coordinate the adjustment of the guns wardly directed guns, and such guns are adjustwith an adjustment of the sighting means, to able for aiming, but almost always heretofore the end that the two may always be kept autoit has been necessary to carry an extra gunner matically in proper coordination. It is then posto aim and fire such rearwardly directed guns. sible to aim the rearwardly directed guns, either IThis constituted an added burden, and if such by maneuvering the airplane, or by adjusting the added weight was to be carried it would be better guns relative` to the airplane, or both, with the to carry additionai ammunition or fuel, or both, result that the field of fire rearwardly is made and without such added weight the ceiling, rate suiciently wide in angle as to afford eiective of climb, maneuverability and other performance protection', especially when it is considered that characteristics of the airplane could be improved. the two opponents will have airplanes of ap- It has been proposed to mount a rearwardly firing proximately equal speed.

The weight of such rearwardly ring guns and their ammunition being appreciable, as compared to the capabilities of such a single-seated lighter, -they will normally be located as close as possible to the lairplanes center of gravity, and

` movable in synchronisrn wil accesos lll-;

pit. However, it possible to suhrlort within the hood. in advance oi the allot and such position that he need shift his line oi vision but slightly, sighting means which include a rear-view mirror i. lf desired, or il necessary, he may have two sighting means, one for ci the guns ll't and il. Any convenient sighting may be emn ployed lo. conjunction with such a mirror, or the sighting means may incorporate such a mirror'.

Purely as a convenient suitable means to the end in view, l have illustrated the sighting means which ll shall shortly describa lleiore describing it. however, let me point out that the rear-view mirror il is so positioned relative to the line of vision V from the pilots ave, and with relation to the direction assumed by the barrel oi the gun, that a target, such as an airplane on the tail of the pllots airplane, which is within the mirror l (particularly when it arrives at a given position in that mirror), the lille ci fire of the gun.

The sighting means herein shown includes, in addition to the rear-view mirror a pair of cross hairs il, and the mirror has a central aperture 3d, and similar cross hairs, il are spaced from the cross heirs t2 in the line of vision V or" the pilot, so th t the pilot, looking along the linel. rieles up his te in the mirror t, and keeps the cross hairs and di in align ment, in the line VL llihen these cross hairs are centered on the target which he sees in the mirror d, by redected vision along the line it, the pilot knows that the is in line of lire of his aun. The spaced cross hairs lll and .in effect ha: the line oi vision `V ci" the pilot so that it does not vary by reason of a did'erent positioning of his head. incidentally, since the height of pilots will vary, suitable adjustment may be provided to accommodate this, and to that end the plate Si', carrying the cross hairs il, has been as adglustably mounted at 35i for movement transversely or the line or vision. iin like fashion the mirror may be tilted about a transverse axis till by means such as the set screw it, and thus it may adjusted to bring I it into proper coordination with the position of the gun barrel. The target then seen along the new7 line oi reflected vision R".

It is necessary that 'the sighting means be the gun as the latnd in strich manner the mirror 5l and n all adjusted poter is adjusted :For ai that the coordinatie the gun is sitionsn ,discordia provided to accomplish suol corresponding movement. segment masy be secur i worm pinion. worm pinion tor l or to the al.` themselves, or i accordan precise con eo rleslderatum bc. s) the adjustments means. its h or diagrammi rieti upon sion means re adjus he guns. mmaterial,

y suggestive i is cartransmis id direc tion oi" moll' l motor 2, so that as tl e nut to adlllst the time adn iustiug coi il el he sight ing mechero ,l t e mirror The this will vary," with each instaln precise details The cross hairs ou coordinate lation, and are readily determined once the -cuit contacts di and d2, disposed in Contact with and at opposite sides of a conductive plate li, carried upon the rock shaft ll, but including an insulating segment il?. The insulating segu ment t2 ls so positioned, and is so coordinated with the movement of the gun and the location of the control surface, that it interrupts the current in the firing circuit to the guns during such time as the gun is swinging past the xed control surface 93.

If the elevator may swing into the guns line of lire, it may be notched out to avoid being hit, as at di'. If this is not done, then it is of course essential to prevent firing of the guns whenever the elevator el is swung upward or downward into the guns ileld of fire, yet it is desirable to permit ring of the guns at 'all times except when the control surface swings so far up or down as to bein danger of entering the guns instantaneous line of flre. Accordingly, in such an arrangement, there are means provided, interconnecting between the firing controls of the guns and the controls for the elevator 9|, so that tiring of the guns is further nterdicted by interfering movement of the elevator.

The normal controls of the elevator include a mast 95 and cables ll'lU and QlD extending forwardly to the pilots cockpit, or their equivalents, connected to the usual control stick there present. Within the main gun-firing circuit 43 is included a normally closed and self-closing switch element #it which is positioned adjacent one of the cables STU or 91D, and upon such cable, for instance the cable STU, properly spaced at either ,side of the switch element M, are provided stops or balls BSU and 99D. Upon sucient movement of the cable S'lU forward or rearward as to cause the elevator 9| to swing upward or downward into the line of .dre of the gun, one of the balls 99D" or 99D will engage the switch element lill and will move it to break the tiring circuit through the lead d3. Neither of the guns can lre so long as the switch iid is open, but this switch is arranged to be closed automatically, as by spring means (not shown), immediately upon movement away of thedeflecting ball lllll'J or 99D. y

The guns iR and lL may be so located that they lire at opposite sides of the vertical iin but may lire in a line so close to the iin that the rudder 92 may in some positions enter the line of ilre of one or the other of the guns. ln similar fashion, then, provision must oe made to disable the interfering gun at such times, it is scarcely feasible to notch out the rudder throughout the distance subtended by the guns angle of lire. The rudder 92 is normally swung by a mast 3G, operated by cables SER and BBL, or the equivalent, extending forwardly to the normal rudder bar (not shown) in the pilots cockpit. Upon each of these cables SBR and -8L there is provided a stop or ball de?, or llSL, corresponding to the balls SEU and 58D, which engages a `switch element 5R or itl; in theshunt firing circuit @3R or dill.' of the corresponding gun iR or iL. In the same fashion as previously described, sufficient movement or" the control ca ble ttl?. or HBL will break the ilring circuit of the gun on the side towards which the rudder is swung, but will keep the other gun in action through its individual shunt circuit MR or ML. The opened shunt is kept open until the rudder has again swung back sumciently toward neutral position that it is out of the line of nre of this particular gun. and then closes automatically. In this way both guns are kept in action to the maximum degree possible, and only one gun. need be disabled momentarily by reason of rt :ider action.

These various safety arrangements operate only during such brief times as there is danger that firing of the guns would carry away some of the control surface of the airplane in which they are mounted, and these safety switches are inmediately self-closing upon the removal of the swung control surface out of the line of fire. In consequence the guns can continue to lire to the greatest possible degree, and are only pre vented from firing, but then automatically, when there is danger of shooting away one of these control surfaces. Adjustment of the guns does not affect the safety switches fidi, MR, and ML, for the opening of these switches is governed by the position of the corresponding control sur face, and not by the position of the guns, yet the guns, whatever may be their position of adjustment, are positively prevented from firing only during such part of their adjustment as directs them toward the fixed horizontal stabilizer 93, or during'a time when a movable control surface ls swung into the firing zone, beyond positions shielded by the fixed surface ahead of it.

The guns are controlled, as is customary, by a firing key Ml in the main lead it. A safety switch fili is likewise provided in this main circuit, as is customary.

The motor 2 is a reversing motor, and is controlled by a., switch 2li. Both the switch 2i) and the firing key lili and safety switch it are arn ranged conveniently to the forwardly facing pilot. The firing key Hit, indeed, may be upon his control stick, as ls customary.

The principles of this invention, particularly as to distantcontrol of a gun upon an airplane, as to the coordination of the sighting means with the adjustable gun, and as to prevention of hrlng of the gun when an aircraft element moves into its line of fire, may be applied equally well to forwardly firing guns, or to airplanes which are other than single-seated planes, where conditions `are such as require such distant control means,

coordinating means, or lire--interdicting means. However, the principles of this invention are best realized and are most valuable in a single-seated military fighter airplane, for reasons given at the outset, and it has been described and will be claimed as applied to such an airplane, without intending, however, to restrict its use only thereto.

What l claim as my invention is:

l, in. combination, in an airplane having con trol surfaces, o. gun mounted, thereon. to past said control surfaces, means to adjust the gun while in flight, through a field of fire which includes the path oi movement of one or more of such control surfaces, controls for operating said control surfaces, controls for firing said gun, con

trols for adjusting said gun, and means interconnecting said three controls to automatically intel-dict operation of the gun while the gunv's field oi? nre includes a control surface, 1n any position of adjustment of the gun or of any such control surface. Y

2. In combination in an airplane having a fuselage and normal control surfaces, including the elevator and rudder, at its tail end, controls for operating the elevator and the rudder, a gun mounted upon the fuselage to fire rearwardly, means to adjust the gun, in flight, through a field of fire which encompasses the elevator, in all its positions, and which may encompass the rudder in certain of its adjustedv positions, controls for firing said gun, and means interengageable between the several controls to automatically interdict firing of the gun while either the elevator or the rudder, in any adjusted position of either the gun or such control surface, lies within the guns field of fire, but the controls for firing the gun being otherwise operable for firing past the elevator or rudder.

3. In combination, in an airplane having normal elevator and rudder control surfaces, and controls for operating each thereof, a gun mount'- ed upon the fuselage and directed through an angle between the two control surfaces, its field of fire including a swung position of each such surface, controls for firing the gun, and means interengageable between the various controls to automatically interdict firing of the gun whenever one or the other such control surface, or both, are swung into the field of fire, but permitting firing of the gun whenever the control surfaces are both out of the guns field of fire.

4. In combination, in an airplane having a fixed surface and a swingable control surface at the trailing edge of the xed surface, a gun mounted upon the airplane and directed to fire past the fixed surface, but including within its field of fire certain swung positions of the swingable control surface, controls for swinging such control surface. controls for firing the gun, and means interengageable between the controls to automatically interdict firing of the gun whenever the swingable control surface lies within its field of re, but permitting firing of the gun whenever such control surface is outside the guns field of're.

5. In combination, in an airplane having a fixed surface and a swingable control surface at the trailing edge of the flxed surface, a gun mounted upon the airplane and directed to fire past the fixed surface, but its field of fire normally including swung positions of the swingable control surface, means to adjust the gun, in flight, through a field of fire which encompasses the fixed surface, controls for so adjusting the gun, controls for swinging the swingable control surface, controls for ring the gun, and means interengageable between the several controls to automatically interdict firing of the gun whenever the gun's field of lire, by reason of adjustnient of the gun or swinging of the control surface, includes the fixed or the swingable surface, but permitting firing of the gun whenever such control surfaces are outside the guns field of re.

JOHN F. HABERLIN. 

